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The High Resolution Chopper Spectrometer (HRC) is installed at the Japan Proton Accelerator Research Complex (J-PARC) and is utilized for a wide range of dynamical studies of materials over a wide energy-momentum space with high resolution. Neutron Brillouin scattering (NBS), i.e., inelastic neutron scattering close to the forward direction, can be performed with the HRC, because this instrument utilizes low angle detectors and high-energy neutrons which facilitates a high resolution. Since the solid angle of the detection area for NBS experiments is limited to very low scattering angles, improvements of the HRC are required to increase the neutron flux with reducing the background. Given the success of the HRC for NBS studies, the neutron intensities for NBS experiments have been improved by changing the detector layout, reducing deformation of the slit package during rotation of the Fermi chopper, and fabricating a longer collimator. At present, we have made further improvements. At around the incident neutron energy Ei = 100 meV, the neutron flux was significantly increased for an energy resolution of ΔE∕Ei = 2%, and the best energy resolution achieved was nearly 1% resolution with an acceptable neutron flux.

The High Resolution Chopper Spectrometer (HRC) installed at MLF, J-PARC provides opportunities for dynamical studies of materials over a wide energy-momentum space with high resolution. Three types of inelastic neutron scattering experiments can be performed with the HRC: high-resolution experiments in a conventional energy-momentum space, eV neutron spectroscopy, and neutron Brillouin scattering (NBS). Some results have been obtained using these techniques. The NBS option makes the HRC different from other chopper spectrometers. Coherent excitations in non-single-crystal samples can be observed with NBS. On the HRC, NBS experiments were made feasible by reducing the background noise at low scattering angles, and some results were obtained.

Neutron Brillouin scattering (NBS) experiments can be performed on the High Resolution Chopper Spectrometer (HRC). Recently, an intensity gain of a factor 2.4 with an improved resolution for NBS has been obtained by improving the detector system, the Fermi chopper, and the collimator system. This improved performance provides opportunities for intense studies of dynamics in condensed matter by using non-single-crystal samples.

A new hybrid-type anvil device for high-pressure single-crystal neutron diffraction experiments is described. The device is composed of a large sapphire anvil and a tungsten carbide (WC) anvil which has a hollow in the center of the culet. In a feasibility test of the device, we could generate the pressure up to 5 GPa with high stability. As an example of the application of the hybrid-anvil device, we show some results of magnetic neutron diffraction experiments on filled skutterudite compound PrFe 4 P 12 .

We improved the High Resolution Chopper Spectrometer (HRC), which is installed at MLF in J-PARC, in order to perform neutron Brillouin scattering (NBS) experiments, and successfully demonstrated a feasibility of this method. Gapless spin-wave excitations were observed in La0.8Sr0.2MnO3, which were in good agreement with previous results using single crystals, on the other hand, a large energy gap in the ferromagnetic spin waves was found in SrRuO3. Spin-wave peaks in a permanent magnet Nd2Fe14B were on the dispersion curve determined previously using a single crystal. Excitations, so-called fast sound, in liquid D2O were in a good agreement with previous inelastic neutron scattering experiments and the dispersion curve were extended to the lower Q region.

The High Resolution Chopper Spectrometer (HRC) was installed at J-PARC, to study dynamics in condensed matters with high-resolutions and relatively-high-energy neutrons. Although the HRC was damaged by the earthquake disaster, we recovered and started neutron scattering experiments. During the recovery works, we also improved the performance of the HRC, by installing a supermirror guide tube, a collimator system, an experiment control environment etc.

The neutron Brillouin scattering (NBS) method was employed at the High Resolution Chopper Spectrometer (HRC) installed at J-PARC. With the recent developments in pulsed neutron sources that can realize high-energy incoming neutrons, the NBS method can be explored to facilitate further developments in material science. As a typical example, ferromagnetic spin waves in a polycrystalline sample of La0.8Sr0.2MnO3 were measured. Spin waves with a Q2 dispersion relation were clearly observed, which agreed well with previous studies that used single crystals.